Analogic Corp. and private-equity firm Altaris Capital Partners said late Tuesday an affiliate of Altaris has agreed to buy Analogic, a maker of medical-imaging products, for $1.1 billion, or $84 a share. Analogic's board of directors has unanimously approved the deal, which is expected to close in mid-2018 and is subject to customary approval and closing conditions, the companies said. The offer represents a 25% premium over Analogic's June 7 closing share price of $67.45, a day after the company announced it was putting itself on the sales block.